Azo-dyestuffs



Patented Feb. 20, 1934 v Azo-DYEsTUrFs Friedrich" Felix and Wilhelm Huber,

Switzerland, assignor Basel,

s to Society of Chemical Industry in Basle, Basel, Switzerland No Drawing. Application June 8, 1933, Serial No.

674,965, and

in Sw tzerland July 8, 1932 3 Claims. (01; 26097) According to this invention valuable dyestuffs are obtained by reaction between an unsulfonated diazotized 5-nitro-ortho-aminophenol and an aromatic base substituted at the nitrogen atom 7 by an hydroxyalkyl-group.

These dyestuifs are Obtained by combining diazotized 5-nitro-ortho-aminophenols, such as 5 -nitrorortho-aminophenolof the formula 4 N09 a or 6-chloro-5-nitro-ortho aminophenol of the formula in a solution which is strongly acid towards Congo with an aromatic base containing an hydroxyalkyl-group linked to the nitrogen atom. There are suitable 'as coupling components bases which are capable of coupling and contain at the nitrogen atom an hydroxyalkyl residue and also a free hydrogen atom, for example (w-hydroxyethyl) -aniline of the formula /H Orr-cm-cm-on, (w-hydroxyethyl)' meta-toluidine of the formula N-CHg-CHrOH,

4 (1 (w hydroxyethyl) amino) 2 S-methylbenzeneof the formula I OCHs Orr-om-om-o H,

(3H3 (1- (w-hydroxyethyl) -amino) -2 S-dimethoxybenzene of the formula OCHs N orrrcnr-on;

methoxy- $CH3 also alkyl-hydroxyalkylated and di-hydroxyalky- "corresponds to a CH2' 'CHzOI-I group, and the lated bases, as, for example, ethyl-(w-hydroxf ethyl) -aniline of the formula (hHa-l A. i f9 'OHz- GH OH, dihydroxyethylaniline of the formula I. Hfqr i The dyestuffs obtainable by the invention are excellently suited for dyeing cellulose esters and ethers, especially acetate silk which they dye fast, remarkably pure shades. The shades Jobtainable with the dyestuffs vary from red to violet.

All these dyestuffs arenew. to the "general formula They correspond wherein R1 means an aryl radical of the hen- Zene' series which contains an OH-group' in'or- 8 tho-positon to the -N=N-'group andian NOzgroup in para-position to the same -N'=N-group,

and wherein further R2 means an aryl-radical of the benzene' series which contains an o Ra group in para-positon to the NN-group, Ra meaning an aIkyl g'rtSii'fi-Whichcontains, on the one part, at least two carbon atoms, and, on the other; an OH-group, and R4 meaning hydrogen, alkyl or a substituted alkyl. They form dark powders which dissolve in ethyl acetate to red to Violet solutions, and dye acetate silk or quite generally cellulose esters and cellulose 'ethers from aqueous suspensions fast red to violet tints of great purity. Among these dyestuffs those are particularly valuable-in which the radical R;

radical R4 to a hydrogen atom or an alkyl group.

For dyeing acetate silk the dyestuffs, which are themselves sparingly soluble, are advantageously used in a finely divided form. For this purpose they may be ground with a dispersing agent, for 19 example the sulfonated residues from the manufacture of benzaldehyde or turpentine oil, in presence of water to produce a fine paste; or they may advantageously be converted, by cautiously drying them in presence of a further quantity 1 of the aforesaid or other assistants, such as sulfite cellulose waste liquor, into dry powdered preparations.

The following examples illustrate the invention, the parts being by weight:-

Example 1 O H V 0 C H: I 1 H I \om-om-pn C a Example 2 A diazo-solution prepared from 15.4 parts of 5-nitro-ortho-aminophenol is mixed with a solution of 16.5 parts of ethyl-(w-hydroxyethyD- aniline in dilute hydrochloric acid, and the whole,

OH I Q S Example 3 A diazo-solution prepared from 15.4 parts of 5-nitro-ortho-aminophenol as described in Example 1 .is mixed with a solution of 13.7 parts CHFCHPOH of whydroxyethyl-aniline in dilute hydrochloric acid. After the dyestuif has been formed it is filtered and washed. The dyestuff so obtained is a red powder which dyes acetate silk yellow red shades. The new dyestuff corresponds very probably with the formula Example 4 10 parts of the dyestuff described in Example 1 are stirred with the addition of a suitable dispersing agent, such as Turkey red oil, sulfite cellulose waste liquor, or a sulfonation product of the residue of the manufacture of benzaldehyde so as to form a uniform paste containing 20 per cent. of dyestuff. One part of this paste is very intimately mixed with 10 parts of water of 50 C. and such a quantity of concentrated soap solution that the dye-bath to be made from the mixture will correspond with a soap solution of 2 per mille strength. The whole is diluted with cold water to make 300 parts. Into the emulsion thus prepared are entered 10 parts of acetate silk yarn and moved about. The bath is heated within hour to 75 C. and dyeing is continued for about /2 hour at this temperature. Rinsing and brightening follow. There are obtained vivid red violet shades.

What we claim is:-

1. The dyestufis of the general formula wherein R1 means an aryl radical of the benzene series which contains an OH-group in orthoposition to the N=N-group and an NOz-group in para-position to the same N=N-group, and wherein R2 means an aryl-radical of the benzene series which contains an i group in para-position to the N=N-group, R3 meaning a hydroxyalkyl-group which contains at least two carbon atoms-,and R4 meaning hydrogen or alkyl, which products .form dark powders dissolving in ethyl acetate to red to violet solutions, and dyeing acetate silk or quite generally cellulose ester and cellulose ether from .aqueous suspensions fast red to violet tints of reat 11G purity.

2. The dyestufi of the general formula z 1 wherein m stands forhydrogen, alkyl or alkoxy, y for hydrogen, alkyl or alkoxy, and e for hydrogen, alkyl or 'alkoxy, which products form dark powders dissolving in ethyl acetate to red to violet solutions, and dyeing acetate silk or quite generally cellulose ester and cellulose ether from aqueous suspensions fast red to violet tints of great purity.

3. The dyestuff of the formula H CH3 which product forms a dark powder dissolving in ethyl acetate to violet solutions, and dyeing H acetate silk or quite generally cellulose ester and cellulose ether from aqueous suspensions fast red violet tints of great purity.

FRIEDRICH FELIX. WILHELM HUBER. 

